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Full text of "Text Book Of Mechanical Engineering"

160                               Face Lathe.

standard at /*, which has a circular T groove to receive
clamping bolts, and admit of adjustment at various horizo:
angles, thus obtaining a traversing, surfacing, or oblique ft
The position of the standard is adjusted by loosening its four,
tion bolts, and applying a crowbar to the teeth jj. Feed is gr
by hand, but can be made automatic as a star feed, or by
overhead chain. By the former a star piece is keyed to the si
screw, and a projection on the face plate catches this at ev
revolution, giving it a small turn. By the second, a ch
attached to a crank pin on left end of mandrel, and passing ale
overhead pullies, actuates a ratchet on the slide screw, and gi
a small feed at each rotation.

If a face lathe be especially made for surfacing and very sh
traversing, the bed is placed across the line of centres. (,
Appendix II.,p. 808.)

The Boring Machine.—Figs. 161 and 162, Plate V]
represent two views of a horizontal boring machine designed
Messrs. Buckton & Co. As already mentioned, many bori
machines are made with vertical bars, as for marine engi
cylinders, the object being to balance the boring head, and p-
serve truth of surface; but if the bar b$ made very large as
rigid, as in the example, inaccuracy need not be feared. The
are two classes of horizontal machine: in one the work is fix
on a stationary bed, while the cutters travel, and in the other t
bed and work are advanced, the cutter bar having no longitudir.
movement. The latter is analogous to lathe boring. (^
Appendix //., /. 808.)

Referring to Figs. 130 and 131, Plate V., a cylindrical bar
placed between the lathe centres, and  driven by  catch plal
About half-way along this bar a longitudinal slot is made throu|
it, and a projecting cutter securely wedged therein.   The upp
slides y and z being removed, as well as the bearings q and
Fig. 131 (made separate for the purpose), the work is bolted ;
saddle x, by bolts placed in T grooves s s, and, as the bar rotatj
and gives the cut, the traversing feed advances the work to the toe

Boring machines are made on these principles, being, in fac
lathes specially designed for boring. The bed is made low, an
the fast head-stock high, the loose head-stock dispensed with, aq